1. Field of the Invention
The present invention relates to a device for transmitting pulsed axial percussions to a bore-forming tool, in particular, a drill. The present invention also relate to a method of forming attachment points with such a device.
2. Description of the Prior Art
The use in attachment and extraction technologies of hand-held tools which are provided with a rotary drive for a bore-forming tool, in particular, a drill and which are equipped with a hammer mechanism for generating pulsed axial percussions transmittable to the drill is well known. The axial percussion enhance the extracting effect of the drill, in particular, during drilling of brittle breakable constructional components such as, e.g., concrete, sandstone and the like. A hammer drill of the assignee of the present invention, which is equipped with an electro-pneumatic hammer mechanism which generates axial percussions having a relative high single percussion energy, can serve as an example of a rotary percussion drill used for drilling of the above-discussed materials. For use in the semi-professional field, in particular, by handimen, the so-called percussion drills are equipped with a mechanical hammer mechanism. As mechanical hammer mechanisms, cushioned cam hammer mechanisms, cushioned strap hammer mechanisms, or simple ratchet hammer mechanism, which generate axial percussions with low single percussion energies and which prove to be adequate, can be used.
Another type of hand-held tools has only a rotary drive for a tool received in the hand-held tool chuck. Such tools include, e.g., screw tools or drilling screws produced by the assignee of the present invention. Such hand-held tools can be used for forming bores in ductile breakable constructional materials such as, e.g., wood or metal. For forming bores in brittle, breakable, hard constructional components such as, e.g., concrete, hand-held tools without a percussion-generating hammer mechanism can hardly be used.
A user of a hand-held tool without a hammer mechanism can come across a case when a bore has to be formed in a hard material. However often in such a case, no rotary percussion tool with a hammer mechanism is available. Therefore, there exists a need to be able to form bores in brittle breakable constructional components when a hand-held tool having only a rotary drive is available. Further, a user of a rotary percussion tool with a hammer mechanism, in particular with electro-pneumatic hammer mechanism, can in many cases, e.g., when bores in brick masonry need be formed, encounter a problem when the single percussion energy provided by the hammer mechanism is too high for a particular use. Usually, in such a case, the bore is formed without the percussion back up. This increases the amount of time necessary to form a bore. In addition, the power of a highly efficient rotary percussion tool is not used to a full extent. Therefore, there exists a need to be able to use the capacity of a rotary percussion drill to the fullest in cases when the single percussion energy provided by the hammer mechanism should be limited.
Further, the assignee of the present invention suggested to improve the known attachment technology of direct mounting, when a nail-shaped attachment member is driven into a constructional material, e.g., steel or concrete, with an explosive powder force, and an attachment member is anchored in a preliminary formed bore by using additional means. In accordance with this technology, the formation of a bore in a constructional component and the anchoring of a tubular attachment member in the bore are effected in a single operational step. It is desirable to be able to use the new technology also when anchoring of an attachment member in a brick masonry is necessary. Therefore, a device is needed which would permit to use the known rotary percussion drill having a hammer mechanism for generating pulsed axial percussions with the new direct attachment technology for forming attachment points also in a brick masonry.